Preheat the oven to 325°F (163°C). Line a 12-cup muffin tin with cupcake liners.

Combine Dry Ingredients: In a small bowl, whisk together the flour, baking soda, salt, cocoa powder, and espresso powder (if using). Set aside.

Make Chocolate Mixture: In a large bowl, whisk together the chocolate chips, boiling water, sour cream, vegetable oil, eggs, granulated sugar, and vanilla extract until smooth and well combined.

Combine Wet and Dry: Gradually add the dry ingredients to the wet ingredients and mix until smooth and no lumps remain.

Fill Cupcake Liners: Spoon the batter into the cupcake liners, filling each about 2/3 full. Bake for 18-22 minutes, or until a toothpick inserted into the center comes out clean. Allow the cupcakes to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.

Make Strawberry Powder: In a small food processor, blend the freeze-dried strawberries until they turn into a fine powder. Sift through a fine mesh sieve, discarding solids.

Make the Buttercream: Using a hand mixer or stand mixer, beat the softened butter until creamy (about 2 minutes). Gradually add the sifted powdered sugar, ½ cup at a time, beating until smooth.

Add Flavor: Add the strawberry powder, vanilla extract, strawberry jam, and milk (or chopped fresh strawberries). Beat on medium speed until fully combined. Adjust the consistency by adding more powdered sugar to thicken or more milk/strawberry puree to thin it out.

Make the Ganache: Place the chopped semi-sweet chocolate in a heatproof bowl. In a small saucepan, heat the heavy cream over medium heat until it just begins to simmer. Pour the cream over the chocolate and let it sit for 2–3 minutes to melt. Stir until smooth and glossy. Let the ganache cool slightly before using.

Core the Cupcakes: Use a small paring knife to cut a cone shape out of the center of each cooled cupcake. Set the cone aside.

Fill with Strawberry Jam: Spoon about 1–2 teaspoons of strawberry jam into each hole in the cupcake, then place the "lid" (the bottom part of the cone) back on top to cover the filling.

Frost the Cupcakes: Using a piping bag fitted with your choice of tip (a star tip works great for a decorative effect), pipe the strawberry buttercream on top of each cupcake.

Top with Ganache: Spoon or drizzle the cooled chocolate ganache over the frosting to create a thick, fudge-like topping.

Garnish: Add sliced fresh strawberries, chocolate sprinkles, mini chocolate chips, or chocolate-dipped strawberries for decoration.